1. Field of the Invention
The present invention relates to an antenna of a wireless communication device, and more particularly to a miniature antenna coupled to a battery.
2. Description of Related Art
To the wireless communication technology, a high frequency antenna is developed from single frequency, dual frequency to triple frequency and even to four frequency (Wi-Fi is added), and it's designed and disposed at outside cellular phone to inside. At the present, a wireless communication device needing to be facilitated with an antenna is limited to a cellular phone no more; a device such as wireless communication television, GPS also relies on a successful antenna design to attain to the best efficiency. The current integrated wireless communication devices become more and more, for giving consideration to function and volume, an antenna with a smaller volume is the biggest challenge to antenna designers.
A general cellular phone may be built in with three or four antennas so as to cope with signal receiving and emitting of a device such as cellular phone communication, Wi-Fi, Bluetooth and even digital television. The future wireless standards with a different specification become more and more, few low power wireless transmission standards are possible to enter and be stationed in a cellular phone and more different application requirements appears, matching combinations between antennas, the avoidance of mutual interference between antennas and even the integration of antennas with a different application will be weight-bearing points of the future design.
To the current cellular phone, an antenna space is reduced smaller and smaller such that the performance of an antenna is sacrificed. An outer antenna is mostly adopted previously, the average efficiency thereof is beyond 50%; an internal antenna is mostly adopted at the present, the average efficiency thereof is seldom beyond 50%. A general market available cellular phone also has the efficiency lower than 20% even if it is made by a well-known company. The efficiencies of several slide or rotary phones in some frequency ranges are even only 10% approximately.
Some coupling structures of antenna and battery such as a GPS receiver module coupled to a handset battery discloses in Taiwan Patent No. M291100 comprises a GPS receiver module capable of being electrically connected to a battery contact and used for capturing electric power to execute the satellite signal receiving function and a connecting body used for enabling the GPS receiver module to be inlayed in a battery, in which the connecting body can inlay the GPS receiver module in the battery by means of plastic injection or connect the GPS receiver module to the battery by installing a accepting structure on an outside body of the battery.
A quadratic battery disclosed by Taiwan Patent Publishing No. 200707820 is provided with a ring-typed antenna; the ring-typed antenna is printed on a protection circuit board, and installed in or attached to a battery unit to allow the protection circuit board to be electrically connected to the battery unit to transmit or receive radio frequency signals.